The Question is from neet-chemistry , and it was created by the author Mr. S M HUSSAIN

Question

Two isotonic solutions, A and B, are separated by a semipermeable membrane.  Solution A contains a non-electrolyte solute, while solution B contains an electrolyte solute that dissociates into two ions. Which statement accurately describes the initial net movement of solvent?

Mr. S M HUSSAIN · Accepted Answer

## CORE INFORMATION
✓ **Answer**: C
## CONCEPT FRAMEWORK
	**Primary Concept**: Osmosis and Osmotic Pressure
	**Related Topics**: Isotonic Solutions, Electrolytes, Colligative Properties
	**Prerequisites**: Understanding of solution concentrations and the movement of solvent across semipermeable membranes.
## SOLUTION PATHWAY
**Given Information**:
	* Two isotonic solutions (A and B).
	* Solution A: Non-electrolyte solute.
	* Solution B: Electrolyte solute dissociating into two ions.
**Method & Steps**:
	1. **Understand Isotonic Solutions**: 
		Reasoning: Isotonic solutions have the same osmotic pressure.  Osmotic pressure is the pressure required to prevent the net movement of solvent across a semipermeable membrane.
		Formula/Rule: Osmotic pressure ($\pi$) is related to the concentration of solute particles: $\pi = iMRT$, where 'i' is the van't Hoff factor (number of particles the solute dissociates into), 'M' is the molarity, 'R' is the ideal gas constant, and 'T' is the temperature. 
	2. **Consider the Effect of Dissociation**: 
		Working: Although solution B has an electrolyte that dissociates, the problem states the solutions are isotonic. This means that despite the dissociation into two ions, the *effective* concentration of solute particles in solution B is the same as the concentration of solute particles in solution A. 
		Key Point: Isotonicity implies equal osmotic pressures, regardless of the nature of the solute (electrolyte or non-electrolyte).
	3. **Determine Solvent Movement**: 
		Result: Since the solutions are isotonic, there is no difference in osmotic pressure. Therefore, there will be no net movement of solvent.
		Verification:  Solvent molecules will still move across the membrane, but the rate of movement will be equal in both directions, resulting in no net change.
## OPTION ANALYSIS
[A] :x: Solvent will move from solution A to solution B: Incorrect. This would occur if solution B had a higher osmotic pressure.
[B] :x: Solvent will move from solution B to solution A: Incorrect. This would occur if solution A had a higher osmotic pressure.
[C] ✓: There is no net movement of solvent: Correct. Isotonic solutions have the same osmotic pressure, leading to no net solvent movement.
[D] :x: Solvent will move in both directions at equal rates, but there will be no net change.: This statement is true, but option C is a more direct and accurate answer to the question about *net* movement.
## LEARNING AIDS
	**Common Mistakes**:
		1. Focusing on the number of ions without considering isotonicity:  It's easy to assume that the electrolyte solution will have a higher osmotic pressure simply because it dissociates. However, the problem states the solutions are isotonic, which is the key information.
		2. Confusing isotonic with iso-osmotic: While related, these terms are not always interchangeable, especially when comparing solutions with different types of solutes.
	**Quick Tips**:
		1. Remember that 'isotonic' means equal osmotic pressure.
		2. Visualize the dynamic equilibrium at the membrane: Solvent molecules are constantly moving, but the rates are equal in both directions when solutions are isotonic.

Mr. S M HUSSAIN · Answer

Solvent will move from solution A to solution B.

Mr. S M HUSSAIN · Answer

Solvent will move from solution B to solution A.

Mr. S M HUSSAIN · Answer

The correct Option is "There is no net movement of solvent."

Mr. S M HUSSAIN · Answer

Solvent will move in both directions at equal rates, but there will be no net change.

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